Plate cylinder for rotary printing presses



May 9, 1950 R. SOLO ON PLATE CYLINDER FOR ROTARY PRINTING PRESSES FiledNov. 20, 1948 2 Sheets-Sheet 1 Vu|l:

INVENTOR.

. R W LPH L M N A770 RNEYS May 9, 1950 R. SOLOMON PLATE CYLINDER FORROTARY PRINTING PRESSES' Filed Nov. 20, 1948 2 Sheets-Sheet 2 INVENTOR.RANDOLPH L M N 02....4 M MM ATTORNEYS Patented May 9, 1950 UNITED STATESPLATE CYLINDER FOR ROTARY PRINTING PRESSES Randolph Solomon, Washington,D. C., assignor of one-half to Edward Stewart, Washington,

Application November 20, 1948, Serial No. 61,187

4 Claims.

This invention relates to plate cylinders used in rotary printingpresses and more particularly to the means for clamping and retainingstereotype plates on such cylinders by exerting a circumferentialtension on the plates. 1 lore specifically, it relates to that type ofplate cylinder wherein the plate clamping and retaining means comprisesa gripper unit removably mounted in a longitudinal recess in thecylinder surface and to means for maintaining this unit in place in therecess.

Heretofore, means have been proposed for clamping and retainingstereotype plates on a printing-press-plate cylinder by exertingcircumferential tension on the plates, but certain objectionablefeatures to the use of plate cylinders so equipped are introduced whenthe gripper members of the unit become worn and require replacement.Such replacement of the gripper members requires the removal of asubstantial amount of the machinery at the sides of the press. With thetype of gripper units currently used the removal operation, indicated asbeing necessary for replacement of grippers, is a time consuming andtherefore expensive operation. Additionally, it may result in aconsiderable period of idleness for the whole printing press.

Broadly, the present invention contemplates a structurally simple andeasily applicable means for retaining and looking a gripper unit withinits receiving recess in a plate cylinder and for quickly releasing itfrom such recess when replacement of gripper members is desirable. Suchretaining and locking means is so designed and fitted in the platecylinder that no part or parts of it need be removed from the platecylinder to release the gripper unit and thereby possible loss or damageof the parts incident to removal is obviated, and complete simplicity ofthe mount ing of the unit in the cylinder recess and the removal of ittherefrom are achieved.

More specifically, the present invention contemplates the use of rotarycam-locking shafts rotatably mounted in holes extending through theplate cylinder contiguous and in communication with the cylinder recess.Each of the cam shafts has a portion of its surface flattened throughoutits length so that when rotated to a certain position within itsreceiving hole in the plate cylinder it lies wholly within the hole andwhen rotated to a different position within the hole a portion of itprotrudes into the cylinder recess. Arcuate grooves are so formedlongitudinally in the side walls of the gripper unit that when the unitis in place within the plate cylinder recess these grooves lie oppositethe shaft-receiving holes of the cylinder. The radii of the arcuategrooves are the same as those of the cam shaft holes so that when theunit is in place the cam shaft holes are in fact completed.

For insertion or removal of the unit, the cam shafts must be turned tothe position at which they lie wholly within their cylinder holes. Whenthe unit has been placed in the recess, the cam shafts need merely berotated and the unit will be securely locked in place, a portion of theshafts protruding into the arcuate grooves of the gripper unit. Meansare also provided for preventing rotation of the cam-locking shaftsafter they have been rotated to locking position so that they may notwork around to their gripper-unitreleasing position during subsequentuse of the plate cylinder.

The invention will be further described in connection with theaccompanying drawings in which:

Fig. 1 is a plan view of a gripper unit mounted in a recess of a platecylinder,

Fig. 2 is a view of one end of a plate cylinder having gripper unitsmounted therein and provided with stereotype plates, showing moreclearly the means for rotating the shafts of the gripper units uponwhich are mounted the grippers,

Fig. 3 is a transverse sectional view taken on line 3-3 of Fig. l, thecylinder here shown, however, being provided with stereotype plates,

Fig. 4 is a partial sectional view taken along line 4-4 of Fig. 3,

Fig. 5 is a partial sectional view taken along line 55 of Fig. 2,showing more clearly the flanged end of a rotatable cam-locking shaft,

Fig. 6 is a partial sectional view showing an end securing member at theopposite end of the rotatable cam-locking shaft shown in Fig. 5, and

Fig. '7 is a fragmentary perspective view of a gripper-unit-rotatablecam-locking shaft.

Referring to the drawings, a rotary printingpress-plate cylinder I0,having wear-receiving liners l0 removably secured thereto, is providedwith recesses ll extending longitudinally throughout its length andshaped so as to receive gripper units If by which stereotype plates I3are held in place on the plate cylinder. While a plate cylinder isnormally provided with two gripper units, each of these is identical instructure and operability to the other and therefore but one will bedescribed. The gripper unit comprises a base portion I4, end walls l6and ribbed sections [1 projecting from the base portion at spacedintervals between the end walls. Grippers I8 and I9 are adapted to bemounted opposite one another, in the spaces between the ribbed sections,on shafts 2| and 22, respectively. These shafts are freely rotatablewithin holes 23 and 24 which pass entirely through the end walls andribbed sections of the gripper unit. The. grippers are so mounted on theshafts as by keys 25 that they rotate with the shafts.

Dogs 26 and 21 are keyed to the ends of the shafts 2| and 22,respectively, which protrude from the ends of the gripper unit andextend beyond the corresponding ends of the plate cylinder. Set screws29 and 3|] are threadedly held in the ends of the dogs remote from theshafts and are adapted to have their distal ends abut shoulders 3| ofthe plate cylinder shaft when the gripper unit is in position within onelongitudinal recess H. By taking up on the set screws, the ends of thedogs are forced outwardly from the plate-cylinder shaft, consequentlyturning their respective gripper unit shafts in opposite directions andcausing the plate-engaging tips of the oppositely faced grippers to comecloser together and to exert a greater circumferential tensile strain onthe printing plates.

Holes 33 and 34 are provided in the plate cylinder contiguous and incommunication with the gripper unit recess and extend throughout thelength of the cylinder. Complimentary arcuate grooves 35 and 36 areprovided in the opposite sides of the base portion 14 of the gripperunit and have the same radii as do holes 33 and 34 in the platecylinder, and are so located in the opposite sides of the gripper unitthat when the gripper unit is placed in the cylinder recess they arerespectively opposite holes 33 and 34.

Rotatable cam shafts 39 and 40 are provided, each havin one end flangedas at 4! and 42 (shown in Fig. respectively, and fit into holes 33 and34 of the plate cylinder. Each cam shaft has a flat surface portion 43extending throughout its length so that when it is turned to apredetermined position it will lie wholly within its receiving hole inthe plate cylinder. The ends of the cam shafts remote from the flangedends threadably, or in any other suitable manner, receive securingmembers 44 and 45 as shown in Fig. 6. The cam shafts when once insertedin the plate cylinder and securably held therein, by their flanged endsand the application of securing members 44 and 45 need not be removed.Polygonal kerfs 4B, of the type which are adapted to receive Allenwrenches, are provided in the flanged ends of the cam shafts and in thesecuring members for tuning them when it is desired to insert thegripper unit into the cylinder recess or to remove it therefrom.

To insert the gripper unit into a cylinder, the cam shafts are firstturned until they lie wholly within holes 33 and 34. The gripper unit isthen placed in the cylinder recess and the rotatable cam shafts arerotated, causing an arcuate portion of each to be received by thecomplimentary arcuate grooves 35 and 36. This locks the unit in thecylinder and prevents its removal. To release the unit the reverseprocedure is followed. The flanged ends of the cam shafts and thesecuring members 44 and 45, in addition to providing means formaintaining such shafts within the cylinder, prevent longitudinalmovement of the gripper unit in the cylinder because of the fact thatthey overlap the ends of the arcuate grooves.

Locking screws 49 are provided in order to prevent the cam shafts fromaccidently turning during the use of the printing press and therebyreleasing the gripper unit. They are threadedly received in the cylinderends adjacent the cam shaft holes. Grooves 5| are formed in the edges ofthe flanged ends of the cam shafts and in the heads of the securingmembers 44 and 45, and are so positioned therein as to receive thelocking screw heads when the cam shafts are in position to maintain thegripper unit in place. The lock.

ing screws need not be removed entirely from the cylinder when it isdesired to turn the cam shaft but only a sufficient distance to havetheir heads fully withdrawn from the grooves 5!. The locking screws alsomay be of the type that are operable by Allen wrenches so that if whenplaced in a printing press the plate cylinder has parts of the pressadjacent its ends which narrowly confine the space available in which towork the gripper-unit-locking means may nevertheless be operated.

It should be clearly understood that varioul modifications may be madein the disclosed ap-\ paratus without departing from the invention orsacrificing the advantages thereof, and the scope of the invention islimited only to the extent set forth in the appended claims.

I claim:

1. In a rotary printing-press-plate cylinder having alongitudinally-extending recess at the periphery thereof, aplate-gripper unit removably mounted in said recess, a shaft rotatablymounted in the gripper unit and extending longitudinally thereof,plate-gripping means non-rotatively mounted on and extendinglongitudinally of said shaft, means for selectively rotating said shaftin directions to move said gripping members transversely of the cylinderto plate-gripping and ungripping positions, at least one of the sides ofthe plate-gripper unit opposite the sides of the recess in the cylinderhaving a longitudinally-extending groove, the cylinder having alongitudinally-extending groove in the sidewall of the recess oppositethe groove in the plategripper unit, an elongated rotatable cam-lockingmember in the groove of the cylinder, and means for selectively rotatingsaid cam-locking member to positions in which a portion thereof extendsinto the groove in the plate-gripper unit and locks the plate-gripperunit in the recess in the cylinder and in which the cam-locking memberlies wholly without said groove to permit removal of the plate-gripperunit.

2. The structure set forth in claim 1 which includes means threadablymounted in an end of the cylinder for preventing rotation of theelongated cam-locking member when the latter is in its locking position.

3. The structure of claim 1 in which the means for rotating the shafthaving the plate-gripping members mounted thereon comprises a memberfixedly mounted on one end portion of said shaft and a screw threadedlymounted in said member and having one end thereof engageable with ashoulder of the cylinder.

4. The structure of claim 1 in which each of said sides of theplate-gripper unit and the recess have the longitudinally-extendingcooperating means for locking the plate-gripper unit in the cylinderrecess.

RANDOLPH SOLOMON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 868,263 Goss Oct. 15, 19071,262,185 Drew Apr. 9, 1918 1,276,336 Drange Aug. 20, 1918 1,384,590Bottone July 12, 1921 1,503,074 Swift July 29, 1924

